1. Field of the Invention
The present invention generally relates to a touch screen, and more specifically to an electromagnetic sensing touch screen using the frequency drift of the specific electromagnetic wave to detect the finger(s) location and implement a function of multipoint touch and display.
2. The Prior Arts
Modern computers use graphic user interface as human to machine interaction, mouse, keyboard and touch screen are commonly used as input device. The touch screen can be constructed in many ways, and some typical examples of common technologies to build touch sensors are shown below:
1. Resistive type touch sensor
2. Surface capacitance
3. SAW
4. IR
5. Projected capacitance
Different sensing method can provide different application problems in final application environment, for example the Projected capacitance touch sensor will be affected by radio frequencies emissions that nearby the harmonic of PCT touch sensor scanning frequency, the touch controller may report false information cause by the radiate radio noise.
It is therefore new technique developed to overcome false operation caused by radiate radio emissions nearby scanning harmonics, an electromagnetic sensing touch screen can overcome the RS problems by receiving beacon RF signals that fingers touch can affect such receiving and can be detected by controller that no ambient radiate can interference this new method.
Therefore, it is greatly needed for an electromagnetic sensing touch screen to implement wirelessly selecting and controlling the smart television by use of a wireless touch screen device provided with wireless control and touch screen functions, which is further enhanced by a smart set-top box and a wireless router, thereby solving the above problems in the prior arts.